linux-kernel - Re: [PATCH 1/7] dt-bindings: media: i2c: Add DW9718S, DW9719 and DW9761 VCM

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Message-ID: <20250820215619.GA1381920-robh@kernel.org>
Date: Wed, 20 Aug 2025 16:56:19 -0500
From: Rob Herring <robh@...nel.org>
To: André Apitzsch <git@...tzsch.eu>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, devicetree@...r.kernel.org,
	Sakari Ailus <sakari.ailus@...ux.intel.com>,
	Daniel Scally <djrscally@...il.com>,
	~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	Val Packett <val@...kett.cool>
Subject: Re: [PATCH 1/7] dt-bindings: media: i2c: Add DW9718S, DW9719 and
 DW9761 VCM

On Sun, Aug 17, 2025 at 07:09:20PM +0200, André Apitzsch wrote:
> Document Dongwoon DW9718S, DW9719 and DW9761 VCM devicetree bindings.
> 
> Signed-off-by: André Apitzsch <git@...tzsch.eu>
> 
> --
> 
> The possible values for sac-mode and vcm-prescale of DW9719 and DW9761
> are missing because there is no documentation available.
> ---
>  .../bindings/media/i2c/dongwoon,dw9719.yaml        | 115 +++++++++++++++++++++
>  1 file changed, 115 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/dongwoon,dw9719.yaml b/Documentation/devicetree/bindings/media/i2c/dongwoon,dw9719.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..80fd3fd42327fcafe3ff209d1cd6bbe17b8a211b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/dongwoon,dw9719.yaml
> @@ -0,0 +1,115 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/dongwoon,dw9719.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Dongwoon Anatech DW9719 Voice Coil Motor (VCM) Controller
> +
> +maintainers:
> +  - devicetree@...r.kernel.org

No. Must be someone that has the h/w or cares about it. If there is no 
one, then we don't need the binding.

> +
> +description:
> +  The Dongwoon DW9718S/9719/9761 is a single 10-bit digital-to-analog converter
> +  with 100 mA output current sink capability, designed for linear control of
> +  voice coil motors (VCM) in camera lenses. This chip provides a Smart Actuator
> +  Control (SAC) mode intended for driving voice coil lenses in camera modules.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - dongwoon,dw9718s
> +      - dongwoon,dw9719
> +      - dongwoon,dw9761
> +
> +  reg:
> +    maxItems: 1
> +
> +  vdd-supply:
> +    description: VDD power supply
> +
> +  dongwoon,sac-mode:
> +    description: |
> +      Slew Rate Control mode to use: direct, LSC (Linear Slope Control) or
> +      SAC1-SAC6 (Smart Actuator Control).
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum:
> +      - 0   # Direct mode
> +      - 1   # LSC mode
> +      - 2   # SAC1 mode (operation time# 0.32 x Tvib)
> +      - 3   # SAC2 mode (operation time# 0.48 x Tvib)
> +      - 4   # SAC3 mode (operation time# 0.72 x Tvib)
> +      - 5   # SAC4 mode (operation time# 1.20 x Tvib)
> +      - 6   # SAC5 mode (operation time# 1.64 x Tvib)
> +      - 7   # SAC6 mode (operation time# 1.88 x Tvib)
> +    default: 4
> +
> +  dongwoon,vcm-prescale:
> +    description:
> +      Indication of VCM switching frequency dividing rate select.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +required:
> +  - compatible
> +  - reg
> +  - vdd-supply
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: dongwoon,dw9718s
> +    then:
> +      properties:
> +        dongwoon,sac-mode:
> +          default: 4
> +        dongwoon,vcm-prescale:
> +          description:
> +            The final frequency is 10 MHz divided by (value + 2).
> +          minimum: 0

That's already the minimum being unsigned.

> +          maximum: 15
> +          default: 0
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: dongwoon,dw9719
> +    then:
> +      properties:
> +        dongwoon,sac-mode:
> +          default: 4
> +        dongwoon,vcm-prescale:
> +          default: 96
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: dongwoon,dw9761
> +    then:
> +      properties:
> +        dongwoon,sac-mode:
> +          default: 6

At the top-level you already said the default is 4. The if/then is an 
AND operation. 'default' is just an annotation and has no effect on 
validation. I would just drop it from the if/then altogether. It's not 
worth the complexity.

> +        dongwoon,vcm-prescale:
> +          default: 62
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        actuator@c {
> +            compatible = "dongwoon,dw9718s";
> +            reg = <0x0c>;
> +
> +            vdd-supply = <&pm8937_l17>;
> +
> +            dongwoon,sac-mode = <4>;
> +            dongwoon,vcm-prescale = <0>;
> +        };
> +    };
> 
> -- 
> 2.50.1
>